Modelling and analysis of soccer heading and protective headgear to understand and prevent mild traumatic brain injury

摘要

The uniqueness of soccer is the fact that one is allowed to use the head to direct the ball in the game. This purposeful ball-to-head impact has become one of the causes of head injuries in soccer. Clinical studies have linked multiple soccer headings with the risk of sustaining mild traumatic brain injury. This study attempts to look into this matter from the engineering perspective. An analytical model of ball-to-head impact was developed based on the mass-spring-damper system. The model predicts the linear acceleration of the skull and brain during an impact with a soccer ball. Validation against dropped-ball experiments and published experimental studies demonstrates a good agreement between the predicted linear head accelerations and those of the experiment and literature. Moreover, finite element model of a soccer ball was developed and validated against ball impact experiment and a published model. The predicted ball impact characteristics were congruous with those measured in the experiment. Further, parametric studies show that the head angle during impact and the ball pressure influence the head responses due to soccer heading. Hence, a proper heading technique and ball pressure is vital to reduce the risk of sustaining brain injury. Moreover, a human head finite element model was adopted from a previous study and validated against a published cadaveric experimental data of intracranialudpressures and linear head acceleration. A good agreement was reached between the predicted head responses and those of the cadaveric experiment. The validated soccer ball and human head finite element models were assembled to perform soccer heading simulations. To validate the finite element analysis, a soccer heading experiment was conducted on human volunteers. An instrumented mouthpiece was used to record linear and angular head accelerations during the soccer heading trials. The simulation results match those of the experiment with more than 80% accuracy. Furthermore, the study aims to evaluate theudefficacy of impact-absorbing foams in mitigating the risk of sustaining head injury due to soccer heading. Another soccer heading experiment was carried out with the volunteers wearing a commercial soccer headgear. The linear and angular head accelerations obtained were compared to those of without wearing the headgear. The results demonstrate that the headgear is incapable of reducing the risk of head injury. Finite element analysesudof soccer heading with wearing the headgear were performed. The comparison of both results reveal a good agreement, which suggest that the finite element models developed is a useful tool in the development of a new protective headgear for soccer players. In addition,udparametric studies of the foam material properties show that an elastomeric foam alone might not be able to attenuate the risk of sustaining head injury due to soccer heading. Further works on the design of the headgear and the use of composite materials in the headgear design is recommended.